Purnamasi

Purnamasi or purnima is the night of the full moon and is associated with the moon-god Chandra, also known as Soma. Chandra was the son of the sage Atri. (This is what the other Puranas also state. And as pointed out earlier, this contradicts the earlier statement.)

Chandra was married to twenty-seven of Daksha’s daughters. These were the nakshatras (stars). Chandra was however inordinately fond of Rohini and neglected his other wives in comparison. The other wives went and complained about this treatment to their father, Daksha. Despite his father-in-law’s warning. Chandra continued to favour Rohini. This angered Daksha and he cursed his son-in-law that he would gradually waste away. The moon became thinner and thinner, and ultimately vanished entirely on the night of amavasya.

Medicinal herbs thrive in the presence of the moon. When the moon disappeared, these herbs wilted and lost all their potency. The gods restorted to Vishnu and Vishnu advised them to churn the ocean. Mount Meru was to be used as the churning rod and the great snake Vasuki was to be used as the rope for the churning.